Magnetic, thermal, and topographic imaging with a nanometer-scale SQUID-on-cantilever scanning probe

Abstract

Scanning superconducting quantum interference device (SQUID) microscopy is a magnetic imaging technique combining high-field sensitivity with nanometer-scale spatial resolution. State-of-the-art SQUID-on-tip probes are now playing an important role in mapping correlation phenomena, such as superconductivity and magnetism, which have recently been observed in two-dimensional van der Waals materials. Here, we demonstrate a scanning probe that combines the magnetic and thermal imaging provided by an on-tip SQUID with the tip-sample distance control and topographic contrast of a non-contact atomic force microscope (AFM). We pattern the nanometer-scale SQUID, including its weak-link Josephson junctions, via focused ion beam milling at the apex of a cantilever coated with Nb, yielding a sensor with an effective diameter of 365 nm, field sensitivity of 9.5 $\text{nT}/\sqrt{\text{Hz}}$ and thermal sensitivity of 620 $\text{nK}/\sqrt{\text{Hz}}$, operating in magnetic fields up to 1.0 T. The resulting SQUID-on-lever is a robust AFM-like scanning probe that expands the reach of sensitive nanometer-scale magnetic and thermal imaging beyond what is currently possible.

17 pages, 4 figures, 6-page supplementary information

References in corpus (6)

• Artificial "spin ice" in a geometrically frustrated lattice of nanoscale ferromagnetic islands
• Persistent currents in normal metal rings
• Imaging resonant dissipation from individual atomic defects in graphene
• Vortex trapping and expulsion in thin-film YBCO strips
• Josephson junctions and SQUIDs created by focused helium ion beam irradiation of YBa${}_2$Cu${}_3$O${}_7$
• A Terraced Scanning Superconducting Quantum Interference Device Susceptometer with Sub-Micron Pickup Loops

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• Fabrication of Nb and MoGe SQUID-on-tip probes by magnetron sputtering
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• Quantum Heat Under the Microscope: A Perspective on Cryogenic Scanning Thermal Microscopy
• Hearing the light: stray-field noise from the emergent photon in quantum spin ice